Novel Core-Shell Structured Ironbark-Like TiO2 as Fillers for Excellent Discharged Energy Density of Nanocomposites

Abstract

The perpendicular orientation of nanowires to electric fields would greatly improve the breakdown strengths (Eb) of polymer-based nanocomposites, however, the relatively small polarization at small filler fraction, and thus the unsatisfactory discharged energy density (Ud), greatly restrict their further application. In this study, x vol.% TO@TO/PVDF nanocomposites with superior energy storage performances have been fabricated, where the ironbark-like TiO2 fillers (TO@TO) with core-shell structures lead to greatly enhanced polarization and Eb simultaneously. The former is due to the coupling effects of the increased interfacial polarization, the latter is due to the enhanced path tortuosity of electric tree growing at small TO@TO fraction. Strikingly, an excellent Ud of 13.1 J/cm3 was achieved in the 1.5 vol % TO@TO/PVDF nanocomposite at 383 MV/m, which is greatly increased by 220% compared with that of pure PVDF (5.98 J/cm3). The primary results might provide a strategy to design and fabricate nanocomposites with satisfactory energy storage performances as well as the flexible and easy-processing ability at small filler fraction.